The Supreme Court handed the Obama administration yet another major win for its environmental agenda on Tuesday, upholding an EPA rule aimed at preventing some states from polluting their downwind neighbors with harmful emissions from sources like coal-burning power plants.

The 6-2 decision overturns a lower court’s judgment that the Cross-State Air Pollution Rule overstepped the agency’s Clean Air Act authority. The rule’s opponents included utilities, industry groups and “upwind” states like Texas, Virginia and Ohio.

The ruling is the latest in a string of court victories for President Barack Obama’s EPA, which has successfully defended scores of major regulations on issues like mercury pollution from power plants and limits on greenhouse gases. The success rate stands in contrast to the George W. Bush administration, whose regulatory efforts on many of the same issues were rejected in court.

“This is great news for millions of people who suffer from serious health problems caused by the soot and smog-causing pollution from power plants in other states,” said John Walke, the clean air program director at the Natural Resources Defense Council.

Justice Ruth Bader Ginsburg wrote for Tuesday’s majority that the agency had followed the “plain text” of the Clean Air Act in enacting the cross-state rule, which is also known as the Transport Rule.

Several “upwind” states, along with some labor and industry groups, argued that EPA should give them a chance to write their own plan to cut emissions. But the Supreme Court rejected that argument, writing that EPA wasn’t required under the law to give them that chance.

The justices also rejected arguments that the method EPA used to divvy up pollution reductions among each state cannot consider the costs of implementing the cuts. EPA’s rule divided up the cuts by considering which would be the cheapest to make, a scheme that critics said would lead to some states cutting more pollution than they contribute. But the court said EPA’s method was “permissible, workable, and equitable.”

Justices Antonin Scalia and Clarence Thomas dissented from the ruling, while Justice Samuel Alito recused himself for unspecified reasons.

The cross-state rule was designed to address pollution that floats from certain states, mostly in the Midwest and South, into other states, mostly along the East Coast. It was also the latest in a long string of federal attempts to address pollutants such as sulfur dioxide and nitrogen oxides that cross state borders. The rule requires 28 states to reduce their emissions.

Downwind states such as New York, North Carolina and Illinois supported the rule, saying the pollution drift was so bad that they couldn’t meet federal air quality standards even if they eliminated all of their own pollution sources.

Previous attempts to tackle cross-state pollution have come up short.

The most recent attempt was a George W. Bush-era rule called the Clean Air Interstate Rule, which courts struck down in 2008 for not doing enough to protect public health. The Clinton administration made an earlier attempt with a rule targeting cross-state emissions of nitrogen oxides.

Determining how certain states are contributing to certain other states’ pollution problems isn’t like simply drawing an arrow on a map. In a brief in the rule, EPA itself described the pattern as a “dense, spaghetti-like matrix,” a phrase the justices cited again during oral arguments.

Scalia objected in his dissent that the majority “treats the text of the Clean Air Act not as the source and ceiling of EPA’s authority to regulate interstate air pollution, but rather as a difficulty to be overcome in pursuit of the Agency’s responsibility to ‘craf[t] a solution to the problem of interstate air pollution.’”

Scalia was especially critical of the majority’s opinion that EPA’s cost-based allocation is acceptable. It may be the best method, he wrote, but it amounts to an “undemocratic revision of the Clean Air Act.”

“The majority reaches its result (‘Look Ma, no hands!’) without benefit of text, claiming to have identified a remarkable ‘gap’ in the statute, which it proceeds to fill (contrary to the plain logic of the statute) with cost-benefit analysis — and then, with no pretended textual justification at all, simply extends cost-benefit analysis beyond the scope of the alleged gap,” Scalia wrote.

He also criticized EPA for not giving the states more time to reach attainment without a federally mandated plan.

The court majority noted that emissions allocation is difficult because pollution in downwind states doesn’t come from any single upwind state.

Considering costs is not prohibited by the Clean Air Act, the justices ruled. They wrote that the rule’s approach is “efficient because EPA can achieve the same levels of attainment, i.e., of emission reductions, the proportional approach aims to achieve, but at a much lower overall cost.” And it’s “equitable because, by imposing uniform cost thresholds on regulated States, EPA’s rule subjects to stricter regulation those States that have done less in the past to control their pollution.”